top speed fail

[mekos]

My 25 hp Mercury two stroke outboard with  remote control, starts fine, idles fine, throttles up fine ....when not in gear, forward or reverse. In gear the engine revs up smoothly but seems to run out of travel and never reaches full throttle. This  started happening once in awhile, now seems as though what ever was starting to fail has now failed. It seems like a cable adjustment, but am hoping someone may have had a similar problem and can point me in the right direction. Thank you for any help.

[Bamby]

I'd check the fuel filter(s) first myself. An unladen engine will seemingly perform well running it through it's paces because it doesn't require much fuel to pull it off. Sustaining a real or normal load requires substantially more fuel, and a plugged up filter will deprive it therefor possibly creating your problem.

[RcgTexas]

a bad power pack or coil will do that too.

[mekos]

Thank you, I pulled the plugs out and one of them was cleaner than the other so swapped them when I put them back in which made no difference. I also noticed a gas smell, and some raw fuel on top of water. This makes me think that fuel delivery is ok, but lack of spark may be the problem. A fellow boater agrees with Texas that its a switch box? or power center? or coil problem. I wouldnt know how to replace any of those items so I may be pulling her out of the lake prematurely and hauling it to a marina $$$$.

[Grumman]

Coil, Common Problem. Shouldn't be too hard to change, all I needed on my Johnson was a 7/16ths wrench and a flat screwdriver

[mekos]

Ive since replaced both spark plugs, warmed it up, put it in gear slowly throttled up, and at about midway she surged and took off like a new boat, I made a couple of high speed laps enjoying the power and then docked . I let the engine cool down, restarted it, took off and now it runs like a dog again ?????